Some of the world's most incredible engineering projects now lie in ruins. These deserted places are home to extraordinary mysteries and untold secrets, and we revisit them to understand how they were built, and why they were abandoned.

Go inside the abandoned city of Chernobyl to follow an investigation into the truth behind the nuclear meltdown there over 30 years ago. New evidence reveals that this accident may be one of the greatest sabotages in history.

Uncover the secrets of Nazi engineering projects that now lie in ruins. These deserted places are home to extraordinary mysteries and untold secrets, and are revisited to understand how they were built, and why they were abandoned. This episode is a compilation of segments from S01E01, "Nazi Ghost Town", S01E05, "Soviet Doomsday Device", and S01E04, "Wild West Apocalypse".

Uncovering the secrets of Soviet engineering projects that now lie in ruins; these deserted places are home to extraordinary mysteries and untold secrets, and we revisit them to understand how they were built, and why they were abandoned. This episode is a compilation of segments from S01E03, "Phantoms Of Chernobyl", S01E01, "Nazi Ghost Town", and S01E05, "Soviet Doomsday Device".

Uncovering the secrets of military engineering projects that now lie in ruins; these deserted places play home to extraordinary mysteries and untold secrets; revisiting them to understand how they were built and why they were abandoned. This episode is a compilation of segments from S01E02, "Curse Of Hell Island", S01E03, "Phantoms Of Chernobyl", S01E04, "Wild West Apocalypse".